﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    
    class Program
    {
        
        static void Main(string[] args)
        {
            double r = 3;
            Console.WriteLine("圆的面积为：" +r*r*Math.PI);
            Console.WriteLine("圆的周长为："+2*Math.PI*r);
        }
    }
}
